UNIX / Linux Find File Owner Name

Q. How do I find out the name of file / directory owner under UNIX / Linux operating systems?

A. You can use ls -l command (list information about the FILEs) to find our the file / directory owner and group names.

The -l option is known as long format which displays Unix / Linux / BSD file types, permissions, number of hard links, owner, group, size, date, and filename. In some environments and UNIX versions / Linux distributions, providing the option --color (for GNU ls) or -G (FreeBSD ls) causes ls to highlight different types of files with different colors.

(Fig. 01: Linux file colors)

(Fig. 02: Understanding Linux / UNIX file colors code [ image credit wikipedia] )

How do I find out owner / group name for a file?

Type the ls -l command at a shell prompt:
$ ls -l filename
Sample output:

-rw-r--r-- 1 vivek admin 2558 Jan  8 07:41 filename

Where,

• -rw-r--r-- : file mode
• 1 - number of links
• vivek - Owner name (if user name is not a known user, the numeric user id displayed)
• admin - Group name (if group name is not a known group, the numeric group id displayed)
• 2558 - number of bytes in the file (file size)
• Jan 8 07:41 - abbreviated month, day-of-month file was
  last modified, hour file last modified, minute file last modified
• filename - File name / pathname

ls -l file mode (permissions)

Quoting from the unix ls command man page - the file mode printed under the -l option consists of the entry type and the permissions. The entry type character describes the type of file, as follows:

The next three fields are three characters each: owner permissions, group permissions, and other permissions. Each field has three character positions:

1. If r, the file is readable; if -, it is not readable.
2. If w, the file is writable; if -, it is not writable.
3. The first of the following that applies:
• S : If in the owner permissions, the file is not executable and set-user-ID mode is set. If in the group permissions, the file is not executable and set-group-ID mode is set.
• s : If in the owner permissions, the file is executable and set-user-ID mode is set. If in the group permissions, the file is executable and set group-ID mode is set.
• x : The file is executable or the directory is searchable.
• - : The file is neither readable, writable, executable, nor set-user-ID nor set-group-ID mode, nor sticky.
4. These next two apply only to the third character in the last group (other permissions).
• T : The sticky bit is set (mode 1000), but not execute or search permission.
• t : The sticky bit is set (mode 1000), and is search able or executable.

See ls command man page for more information:
$ man ls

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